Friday, May 13, 2016

A follower asked me a good question today. Are there any good resources to tell pregnant women what to do to limit the risk of Zika exposure? I found various sources but nothing that was as complete as I'd like. With the latest news on Zika virus that it causes birth defects in infected mice, this post is timely.The absolute best way to reduce the risk of Zika would be a vaccine. Unfortunately, we are still many years away from this being available. Failing that, there are other steps that can be taken. In general, any steps to avoid exposure to mosquitoes can help reduce the risk of contracting Zika. However, there are some additional steps that should be taken to further reduce the risk that are specific to Aedes aegypti (a major vector of the Zika virus).

General tips1) Wear long pants and long sleeves whenever outside. This is not the most comfortable thing to do especially in areas where the risk of Zika is the highest, but by giving the mosquitoes less "real estate" to sample, you can lower your risk of being bitten.2) Make sure all window and door screens are in good repair. Also never leave the door or a window open without a screen. Whatever you do, don't invite mosquitoes in for an all you can eat buffet where you are on the menu. 3) Using insect repellent is a must. Every time you leave the house, you need to put some on. There are different types of mosquito repellents and they are not all created equally. DEET is probably the best option as it lasts the longest and is very effective. Other good options are Picaridin and IR3535. These have been shown to be safe and effective. However, some people are not fond of man-made chemicals. A repellent made from naturally occurring compounds does exist, lemon eucalyptus oil. The issue there is that it does not last as long as some of the other repellents, so you have to reapply it if you are outside for long enough. Other natural products are essentially useless and do not last long enough to be of use for anything. I know the suggestion to use lemon eucalyptus oil will be controversial as DEET is safe and effective; however, the risk of Zika during pregnancy is big enough that I would rather someone use an effective product, like lemon eucalyptus oil, than try some of the other natural products or even use nothing at all. We can debate natural versus man-made another time. Just use a repellent that works.Aedes aegypti specific tips

Since Aedes aegypti plays a big role (if not the sole role) in Zika virus transmission, I'll give some advice on how to deal with it. A. aegypti is pretty much a pig. It will live in any standing water that it can. It is very much an urban mosquito as it lives near people in their trash. A. aegypti can often be found breeding in old tires, pots, garbage, basically anything that will hold a little water. So it is vital to clean up any trash that is near your home. If you have a birdbath or pond in your yard, you can treat the water with an insecticide, like pyriproxyfen which is safe to use as it is an insect growth regulator and only targets insects. Another thing to consider is that A. aegypti is a daylight biter and as a result is most active from before sunrise to two hours after sunset. It likes to bite indoors (remember to close doors and windows if they don't have screens) and will often hide in dark rooms. In summation for A. aegypti:

1) Clean up any garbage or standing water that is near your house.2) Treat any standing water in ponds or bird baths with an insecticide (such as an insect growth regulator).3) Make sure you keep doors and windows closed if they are not properly screened. Until a vaccine can be released, it boils down to avoiding the mosquito vectors as much as you can. Simple steps like clearing any potential breeding sites (read standing water) and using an insect repellent will help in this.

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This page is part of an effort to flood social media with science and to engage the public in science-related issues. I work with plant viruses and the arthropods who vector them but I'll cover all aspects of virology here from human pathogens to archaea viruses and everything in between.
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